TLineFitter Class Reference

A class to fit a TTrackBase object to a line. More...

#include <TLineFitter.h>

Inheritance diagram for TLineFitter:

List of all members.

Public Member Functions
	TLineFitter (const std::string &name)
	Constructor.
virtual	~TLineFitter ()
	Destructor.
void	dump (const std::string &message=std::string(""), const std::string &prefix=std::string("")) const
	dumps debug information.
double	a (void) const
double	b (void) const
double	det (void) const
virtual int	fit (TTrackBase &) const
const std::string &	name (void) const
	returns name.
Protected Member Functions
void	fitDone (TTrackBase &) const
	sets the fitted flag. (Bad implementation)
Private Attributes
double	_a
double	_b
double	_det

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Detailed Description

A class to fit a TTrackBase object to a line.

Definition at line 28 of file TLineFitter.h.

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Constructor & Destructor Documentation

TLineFitter::TLineFitter

(

const std::string &

name

)

Constructor.

Definition at line 18 of file TLineFitter.cxx.

: TMFitter(name), _a(0.), _b(0.), _det(0.) {
}

TLineFitter::~TLineFitter

(

)

[virtual]

Destructor.

Definition at line 22 of file TLineFitter.cxx.

                          {
}

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Member Function Documentation

double TLineFitter::a

(

void

)

const [inline]

Reimplemented in TRobustLineFitter.

Definition at line 67 of file TLineFitter.h.

References _a.

Referenced by TRobustLineFitter::fit().

                         {
    return _a;
}

double TLineFitter::b

(

void

)

const [inline]

Reimplemented in TRobustLineFitter.

Definition at line 73 of file TLineFitter.h.

References _b.

Referenced by TRobustLineFitter::fit().

                         {
    return _b;
}

double TLineFitter::det

(

void

)

const [inline]

Reimplemented in TRobustLineFitter.

Definition at line 79 of file TLineFitter.h.

References _det.

Referenced by TRobustLineFitter::fit().

                           {
    return _det;
}

void TLineFitter::dump	(	const std::string &	message = std::string(""),
		const std::string &	prefix = std::string("")
	)			const

dumps debug information.

Reimplemented from TMFitter.

Reimplemented in TRobustLineFitter.

int TLineFitter::fit

(

TTrackBase &

)

const [virtual]

Implements TMFitter.

Reimplemented in TRobustLineFitter.

Definition at line 26 of file TLineFitter.cxx.

References _a, _b, _det, TMFitter::fitDone(), genRecEmupikp::i, Line, t(), TFitAlreadyFitted, TFitErrorFewHits, TFitFailed, and x.

Referenced by TRobustLineFitter::fit().

                                     {

    //...Already fitted ?...
    if (t.fitted()) return TFitAlreadyFitted;

    //...Check # of hits...
    if (t.links().length() < 2) return TFitErrorFewHits;

    unsigned n = t.links().length();
    if (_det == 0. && n == 2) {
        double x0 = t.links()[0]->position().x();
        double y0 = t.links()[0]->position().y();
        double x1 = t.links()[1]->position().x();
        double y1 = t.links()[1]->position().y();
        if (x0 == x1) return TFitFailed;
        _a = (y0 - y1) / (x0 - x1);
        _b = - _a * x1 + y1;
    }
    else {
        double sum = (double) n;
        double sumX = 0., sumY = 0., sumX2 = 0., sumXY = 0., sumY2 = 0.;
        for (unsigned i = 0; i < n; i++) {
            const HepPoint3D & p = t.links()[i]->position();
            double x = p.x();
            double y = p.y();
            sumX  += x;
            sumY  += y;
            sumX2 += x * x;
            sumXY += x * y;
            sumY2 += y * y;
        }

        _det = sum * sumX2 - sumX * sumX;
#ifdef TRKRECO_DEBUG_DETAIL
        cout << "        TLineFitter::fit ... det=" << _det << std::endl;
#endif
        if (_det == 0.) {
            return TFitFailed;
        }
        else {
            _a = (sumXY * sum - sumX * sumY) / _det;
            _b = (sumX2 * sumY - sumX * sumXY) / _det;
        }
    }

    if (t.objectType() == Line)
        ((TMLine &) t).property(_a, _b, _det);
    fitDone(t);
    return 0;
}

void TMFitter::fitDone

(

TTrackBase &

)

const [protected, inherited]

sets the fitted flag. (Bad implementation)

Definition at line 24 of file TMFitter.cxx.

References t().

Referenced by TRobustLineFitter::fit(), fit(), and TCircleFitter::fit().

                                      {
    t._fitted = true;
}

const std::string & TMFitter::name

(

void

)

const [inline, inherited]

returns name.

Definition at line 73 of file TMFitter.h.

References TMFitter::_name.

                         {
    return _name;
}

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Member Data Documentation

double TLineFitter::_a [mutable, private]

Reimplemented in TRobustLineFitter.

Definition at line 49 of file TLineFitter.h.

Referenced by a(), and fit().

double TLineFitter::_b [mutable, private]

Reimplemented in TRobustLineFitter.

Definition at line 50 of file TLineFitter.h.

Referenced by b(), and fit().

double TLineFitter::_det [mutable, private]

Reimplemented in TRobustLineFitter.

Definition at line 51 of file TLineFitter.h.

Referenced by det(), and fit().

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